While arguments differ from state to state, the basic premise is often the same - maps were drawn with heavy influence by one political party to squash the other, killing voter rights along the way. (The Texas cases instead focus on race.)

Texas - The Supreme Court on Jan. 12 added two more redistricting cases to its calendar, agreeing to hear cases involving statehouse and congressional maps in Texas. The court will consider an appeal of a lower-court ruling that districts were drawn to discriminate against blacks and Hispanics. The court decided not to hear separate arguments involving political gerrymandering in Texas. Yet rulings in the Maryland and Wisconsin cases could apply to Texas.

North Carolina - A panel of three federal judges on Jan. 9 struck down the North Carolina congressional maps on gerrymandering grounds, and ordered new maps to be drawn in time for this year's election. The Supreme Court has since delayed the order to toss out the existing maps, allowing time for appeal and any potential guidance from the Wisconsin and Maryland cases. The North Carolina case was brought by Democrats upset with Republican maps.

Pennsylvania - The Democratic-controlled court gave the Republican-controlled legislature until Feb. 9 to pass a replacement congressional map, and Democratic Gov. Tom Wolf until Feb. 15 to submit it to the court, reported pennlive.com. Otherwise, the justices said they would adopt a new map. A Republican spokesman said an appeal was expected to the U.S. Supreme Court. This case is similar to the North Carolina case.